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Chapter 1: Introduction and

Measurement Brent Royuk

Phys-111 Concordia University

Learning Science in a Christian Context

What does it mean that Concordia is a Christian school and how does that affect us in this class?

1.  We know that science is not the most important thing in the world. 2.  We are in a Christian learning community and trust each other as brothers and

sisters in Christ. 3.  We acknowledge scholarship as an important activity for Christians to pursue.

•  “For a Christian, the mind is important because God is important.” -Mark A. Knoll

4.  We enjoy and appreciate learning about the natural world because we know who created it. We marvel at the scientific order and complexity of the universe and seek knowledge with a worshipful attitude.

5.  We recognize that God has called us to our current vocation. At this point in our lives, we have not only chosen to be a student- we have answered God’s call for us to accomplish his work on earth as a student.

6.  “So whether you eat or drink or whatever you do, do it all for the glory of God.” 1 Cor. 10:31

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Prerequisite Skills •  Find the slope of this line:

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Prerequisite Skills •  Given: a = 2, b =3, c =4. Find d.

a= b2

cd22a2b

= dc

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Prerequisite Skills •  Given each of the following equations,

solve for n:

•  Solve for n in terms of b:

ω 2 =2nθb3 = 5n

a2 F =G

m1m2n2

3n=2a+b 2n=2a−4b

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Prerequisite Skills •  For the following triangle find the length

of side AB and the measure of angle C.

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Foundations of Physics •  Before we consider what physics is,

let’s consider science in general. •  How would you answer the question

“What is science?”

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The Scientific Method 1.  Define the question2.  Gather information and resources3.  Form a hypothesis4.  Perform an experiment and collect data5.  Analyze data6.  Interpret data and draw conclusions that

serve as a starting point for new hypotheses7.  Publish results

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Problems with the Scientific Method

•  Too procedural •  There really isn’t a scientific method.

–  the only principle that does not inhibit progress is: anything goes. --Paul Feyerabend

•  Deductive (general to specific) instead of inductive (specific to general)

–  Individual experiments tend to be deductive, but a broad picture of the history and NOS is inductive.

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The Four Processes of Science From Gil Daenzer

1.  Observe Nature (Facts) 2.  Find Order (Laws) 3.  Build Models (Theories) 4.  Explain & Predict

This is a conceptual model for science, rather than a procedural one.

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The Four Processes of Science

Example 1.  I saw a sunrise today (Fact) 2.  The sun rises in the east (Law) 3.  What’s the theory?

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The Four Processes of Science

Example 1.  Drop a rock: it falls (Fact) 2.  Things fall (Law) 3.  What’s the theory?

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Scientific Laws

•  An observed regularity –  Laws are simple.

•  Scientific laws are descriptive, not prescriptive.

•  Scientific laws are discovered, not invented.

•  God makes laws, not man.

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Some Scientific Laws •  Boyle’s Law •  Charles’ Law •  Newton’s Laws of Motion •  Kepler’s Laws of Planetary Motion •  Coulomb’s Law •  Hubble’s Law •  Ohm’s Law •  Maxwell’s Equations •  Snell’s Law •  The Laws of Thermodynamics •  The Law of Definite Composition •  The Law of Conservation of Mass/Energy •  Buys-Ballot's law (wind travels counterclockwise around low

pressure systems in the Northern Hemisphere) •  Geology: The law of stratigraphic succession

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Some More Laws •  Macfarlane's Law

–  You can talk faster than you can type, but you can read faster than you can listen.

•  Godwin's Law –  An adage in Internet culture that states “As an

online discussion grows longer, the probability of a comparison involving Nazis or Hitler approaches one.”

•  Dilbert’s Law –  the most ineffective workers are systematically

moved to the place where they can do the least damage: management.

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Scientific Theories •  A scientific theory is “a well-substantiated

explanation of some aspect of the natural world that can incorporate facts, laws, inferences, and tested hypotheses.” --National Academy of Sciences

•  Theories are the conceptual product of science

•  God doesn’t make scientific theories, we do. •  One-word synonyms: Model, framework,

explanation

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Some Well-Known Scientific Theories

•  Relativity Theory •  Atomic-Molecular Theory •  Kinetic Theory •  Quantum Theory •  String Theory •  Grand Unification Theory •  Germ Theory of Disease •  Plate Tectonics •  Evolutionary Theory •  Evolutionary Psychology

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Problems with the Scientific Method: The Grade-School Scientific Certainty Myth

Wrong:

1.  Hypothesis 2.  Theory 3.  Law

So a Law is a proven theory!

Better:

1. Law 2. Theory 3. Hypothesis

A theory is never proven.

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What is Physics? • Old science

– Natural Philosophy – The “Queen of the Sciences” – “Physics envy”

• All science is either physics or stamp collecting. Ernest Rutherford

• ... it is impossible to explain honestly the beauties of the laws of nature in away that people can feel, without their having some deep understanding of mathematics. I am sorry, but this seems to be the case. Richard Feynman

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Units of Measurement •  Standardization is necessary for science (the king’s

thumb) •  Cubits, Thumb = inch, 12 inches = foot, three feet =

yard •  1793, French Academy of Sciences •  1983: The distance light travels in 1/299,792,458

second

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Units of Measurement •  The kilogram

–  One cubic tenth of a meter of water –  The gram/milliliter/cc connection –  Prototype Pt-Ir cylinder

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Units of Measurement •  Where did the second come from? •  1 sec = 9,192,631,770 oscillations of Cs-133 radiation •  “The speed of time is one second per second.” •  The MKS system vs. cgs, fps •  The liter •  The seven base units

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Prefix Symbol Magnitude Meaning (multiply by)

Yotta- Y 1024 1 000 000 000 000 000 000 000 000

Zetta- Z 1021 1 000 000 000 000 000 000 000

Exa- E 1018 1 000 000 000 000 000 000

Peta- P 1015 1 000 000 000 000 000

Tera- T 1012 1 000 000 000 000

Giga- G 109 1 000 000 000

Mega- M 106 1 000 000

myria- my 104 10 000 (this is now obsolete)

kilo- k 103 1000

hecto- h 102 100

deka- da 10 10

- - 100 1

deci- d 10-1 0.1

centi- c 10-2 0.01

milli- m 10-3 0.001

micro- u (mu) 10-6 0.000 001

nano- n 10-9 0.000 000 001

pico- p 10-12 0.000 000 000 001

femto- f 10-15 0.000 000 000 000 001

atto- a 10-18 0.000 000 000 000 000 001

zepto- z 10-21 0.000 000 000 000 000 000 001

yocto- y 10-24 0.000 000 000 000 000 000 000 00126

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Units of Measurement • Try these:

3.4 cm = ___ m 112000 ng = ___ kg 340 g = ___ kg 3.4 x 10-11 km = ___ mm

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•  Derived units can have funny dimensions –  e.g. 1 J=1 kgm2/s2

•  Sometimes you can decide if an equation is false if it doesn’t work out dimensionally –  e.g.

•  Do math with units:

•  You might also see [a] = m/s2 •  We will do math with units just like with

numbers •  Example: Use v=p/m to find v given p =12 kg

m/s and m = 4.0 kg

Dimensional Analysis

€

v = 2axms= 2 m

s2m

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Converting Units •  These are all velocity units: m/s, ft/s, mph,

cm/min, cubits/week, attoparsecs/microfortnight –  All can be used interchangeably

•  The conversion factor method: 12 ft = ___ yd 34 km/h = ___ m/s 18 kg/m3 = ___ slugs/ft3 1 mph = ___ km/min At desk: 1 mile/(min)2 = ___ m/s2 1 apc/�fortnight = ___ cm/s

•  Fermi: 1 microcentury equals about one lecture period

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Problem Solving

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Problem Solving •  Do it for you, not for me. •  For problem solving, we will use:

Good Form: 1.  Identify Given/Need. 2.  Write the equation to be used. 3.  Algebraically solve for the desired quantity. 4.  Substitute in known values. 5.  Write your answer with units & proper sig-figs.